Cu\p. III. THE NGAMI. 47 



(Acronotus Janata), are swept down by its rushing waters. 

 The trees are gradually driven by the winds to the opposite 

 side, and become embedded in mud. 



The water of the lake is fresh when full, but brackish when 

 low. This region, compared with that from which we had 

 come, was clearly a hollow, the lowest level being Lake Ku- 

 madau. The point of the ebullition of water, as shown by one 

 of Newman's barometric thermometers, was only between 

 207^° and 20G°, which gives an elevation of not much more 

 than two thousand feet above the level of the sea. We had 

 descended above two thousand feet in coming from Kolobeng. 

 A little of that water from the tropical rains, which inundates 

 large tracts of country farther north, flows as far south as 

 20° 20', and fails into the lake as into a reservoir. It is 

 brought by the Embarrah, which divides into the rivers Tzo 

 and Teoughe, and the Tzo again divides into the Tamunak'le 

 and Mababe. Of these the Tamunak'le discharges itself into 

 the Zouga, and the Teoughe into the lake. The flow begins 

 either in March or April, and the descending waters find the 

 channels of all the rivers dried up, except in certain pools in 

 their beds, which have long dry spaces between them. The 

 lake itself is very low. 



The Zouga is only a prolongation of the Tamunak'le, and 

 an arm of the lake reaches up to the point where the latter 

 ends and the former begins. The Zouga is broad and deep 

 when it leaves the Tamunak'le, but becomes gradually nar- 

 rower as it descends for about two hundred miles. It then 

 flows into the Kumadau, a small lake about three or four 

 miles broad and twelve long. The water does not make much 

 progress in filling this lake till the end of June. In Sep 

 tember the rivers cease to run. When the supply has been 

 more than usually abundant a little water gets beyond the 

 Kumadau, and if the quantity were larger it might go further 

 in the dry rocky bed of the Zouga. The channel is perfect, 

 but, before the water finds its way much beyond Kumadau, the 

 upper supply ceases to run, and the rest becomes evaporated. 

 There is, I am convinced, no such thing in the country as a river 

 becoming lost in the sand. This fancied phenomenon haunted 

 me for years ; but I have failed in discovering anything be- 

 yond a most insignificant realisation of it. 



